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Phys. Rev. Lett. 101, 182004 (2008) [7 pages]

Measurement of the Polarization of the Υ(1S) and Υ(2S) States in pp̅ Collisions at s=1.96  TeV

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V. M. Abazov et al. The DØ Collaboration
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Received 18 April 2008; published 31 October 2008

We present a study of the polarization of the Υ(1S) and Υ(2S) states using a 1.3  fb-1 data sample collected by the D0 experiment in 2002–2006 during run II of the Fermilab Tevatron Collider. We measure the polarization parameter α=(σT-2σL)/(σT+2σL), where σT and σL are the transversely and longitudinally polarized components of the production cross section, as a function of the transverse momentum (pTΥ) for the Υ(1S) and Υ(2S). Significant pTΥ-dependent longitudinal polarization is observed for the Υ(1S). A comparison with theoretical models is presented.

© 2008 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.101.182004
DOI:
10.1103/PhysRevLett.101.182004
PACS:
13.88.+e, 13.20.Gd, 14.40.Nd